Source: Wikipedia.
A growing number of major airports are served by rail transit. The SeaTac station for the Seattle area’s Link light rail system opened in 2009. By 2018, about 6,000 passengers per day boarded the train at the airport station. By comparison, in Hong Kong, a larger hub where it is much more difficult to drive one’s car to the airport, boardings on the Airport Express averaged 49,000 per day in 2018.